Blockchain Development | Login with Metamask using NodeJS backend | JWT authentication

Blockchain technology has been gaining popularity in recent years due to its decentralized nature and secure data storage. One of the key features of blockchain development is the use of smart contracts, which are self-executing contracts with the terms of the agreement between the buyer and the seller being directly written into code.

Metamask is a popular browser extension that allows users to run Ethereum dApps in their web browser without running a full Ethereum node. It also provides a secure wallet to store and manage digital assets. In this article, we will discuss how to implement login functionality with Metamask using NodeJS backend and JWT authentication.

NodeJS Backend

NodeJS is a popular runtime environment for building server-side applications. It’s lightweight and efficient, making it a perfect choice for blockchain development. To set up a NodeJS backend for login with Metamask, you will need to install the necessary dependencies using npm or yarn.

“`
npm install express jsonwebtoken web3
“`

Once the dependencies are installed, you can create a server using Express and initialize the web3 instance to interact with the Ethereum blockchain. You will also need to create endpoints for user authentication using Metamask and generate JWT tokens for secure communication between the client and the server.

Metamask Login

Metamask provides a secure login mechanism for blockchain applications by allowing users to sign transactions and verify their identity using their Ethereum wallet. To implement login with Metamask, you will need to integrate the Metamask Ethereum provider in your frontend application and request the user’s signature to authenticate their identity.

“`html
Login with Metamask

async function loginWithMetamask() {
const accounts = await ethereum.request({ method: ‘eth_requestAccounts’ });
const userAddress = accounts[0];
// Send the user address to the server for authentication
// …
}

“`

JWT Authentication

Once the user’s identity is verified using Metamask, the server should generate a JWT token and send it back to the client for secure authentication. The client can then attach the JWT token to the HTTP headers for subsequent requests to the server. This ensures that the user is authenticated for all API calls.

“`javascript
const jwt = require(‘jsonwebtoken’);
// Generate JWT token for the authenticated user
const token = jwt.sign({ user: userAddress }, ‘secretKey’, { expiresIn: ‘1h’ });
// Send the token back to the client
“`

By implementing login with Metamask using NodeJS backend and JWT authentication, you can ensure a secure and decentralized login mechanism for blockchain applications. This not only enhances the user experience but also provides a robust security layer for blockchain transactions.